1. Field of the Invention
This invention relates to a programmable terminal system comprising at least a programmable terminal device and a server device connected to each other through a network.
2. Description of the Related Art
In previously developed systems, a programmable terminal device (hereinafter referred to as the “PT”) may be connected with a programmable logic controller (hereinafter referred to as the “PLC”) and functions as a monitor (monitor device) for displaying the state of a device or a system to be controlled by the PLC. Also, the PT has a display screen in the form of a touch panel which is operated by the user to output a predetermined command to the PLC.
For this purpose, the monitor screen of the PT constitutes a display screen of a flat display panel with a large touch sensor, on which the state of the device to be controlled by the PLC is usually displayed. This monitor screen includes a background data displayed as a background of the monitor screen and figure data including various parts arranged and displayed on the background data. The parts of the figure data include an illustration figure corresponding to the device to be controlled (hereinafter referred to as the “object device”), a push-button switch figure for issuing an operation command to the object device and a display lamp figure indicating the operation status of the object device.
The image of the background displayed over the whole screen of the display panel is hereinafter called the “screen” and the various figures arranged and displayed on the screen are called the “parts”. In what is called the multi-window control, however, the image corresponding to each of the windows (not necessarily enlarged over the whole screen) is called the “screen”, and the information constituting the contents of the screen and the parts the “contents”.
The PT and the PLC are connected communicably with each other. In the case where an input function part such as a push-button switch figure is operated through the touch panel by the user, a CPU making up the control unit of the PT applies an operation signal indicating (current status) to the PLC at an appropriate time to reflect the operation of the particular input function part in the physical unit of the PLC. In similar fashion, by changing the display status of any of the output function parts including various parts on the PT screen, the operation of a particular output function part is displayed on the screen. The parts may, for example, include a display lamp, an alarm lamp, a motor and a solenoid valve. The change in display occurs in operatively interlocked relation with the change in the control status of the PLC as the result of the CPU of the PT fetching the control status of the PLC.
In a more recently developed PT, in contrast, the display function is improved, so that not only the monitor screen for the PLC control status but also various screens including a trouble-shooting screen and a production command screen are adapted to be displayed by appropriately switching on the display screen. Some products placed on the market with the improved display function have as many as 4000 screens in total (see Japanese Patent Application No. 2004-133806).
The trouble-shooting screen is defined as a screen in which in case of trouble with the object device, for example, the job and the knowledge required for restoration are displayed in the form of a figure, a description or an illustration. The production command screen, on the other hand, is a screen in which production commands to the operator are displayed similarly in the form of a figure, a description or an illustration on a production line including the object device. These screens are often switched by the switching operation of the operator through the touch panel or an automatic switching process operatively interlocked with occurrence of a problem. The trouble-shooting screen and the production command screen are arranged on the background screen and therefore can be considered “parts”. The repair work information, the knowledge, figures, description and the illustration displayed in the trouble-shooting screen may also be considered parts. The specifics such as the repair work and knowledge, the figures, the description and the illustration contained in each part correspond to the “contents”.
The trouble-shooting screen and the production command screen are often used to display the accumulation of the production know-how and techniques with the contents data which are highly confidential information for the companies having the PT on the one hand and very useful information for the competitors on the other hand.
In the prior art, all the data required to plot the screen displayed on the display screen are usually stored in a nonvolatile memory (such as a flash memory or a hard disk) of the PT. Generally, the file management system of the nonvolatile memory is fixed in form and the data therein can be read out with comparative ease.
The conventional PT, therefore, poses the problem that the PT itself may be stolen or the data stored in the nonvolatile memory may be stolen by connecting a personal computer to the PT. As a result, the highly confidential information of the enterprise in which the PT is installed may be easily accessed.
Also, the production command screen must often be updated for securing the synchronization among a plurality of production lines. The data format required for plotting the screen, however, is analogous to the CAD unique to each PT, and therefore the data must be created by connecting a personal computer to each PT using an exclusive tool.
In the case where a PT is installed on each production line, therefore, for each update the bothersome job of creating or transferring the data using an exclusive tool must be repeated by connecting a personal computer to each PT.
In addition, the need of operating an exclusive image creation tool instead of a multipurpose OA software leads to the problem that a skilled operator is required to rewrite the data.
This invention has been achieved in view of the aforementioned problems of the conventional PT, and an object of the invention is to provide a PT system, a PT device and a method of managing the PT system in which the screen of arbitrary contents can be displayed on a display screen and the confidential contents can be protected from unauthorized access.
Another object of the invention is to provide a PT system, a PT device and a method of managing the PT system in which the data required to plot the screen can be rewritten without connecting a personal computer having an exclusive tool built therein to each PT.
Still another object of the invention is to provide a PT system, a PT device and a method of managing the PT system in which the data required to plot the screen can be rewritten without connecting a personal computer having an exclusive tool built therein to each PT, and in which multipurpose OA software can be used to rewrite the required contents.
The above and other objects, features and advantages will be easily understood by persons skilled in the art with reference to the following description.